1. Field of the Invention
The present invention relates to a display device and a method for manufacturing the same and more particularly, relates to a display device suitable for being used outdoors.
2. Description of the Background Art
As for the display device used outdoors, preferable display characteristics are required in an environment having a large amount of incident light from an outside of the display device such as a case where it is used under sunlight. Meanwhile, a wiring of the display device is required to be low in resistance and easily processed, so that an aluminum (Al) alloy is increasingly used as metal which satisfies the above requirement.
However, the aluminum alloy is high in reflectivity, and the problem is that incident light reflects on an aluminum alloy wiring, in the environment having the large amount of the incident light from the outside of the display device, so that preferable display characteristics cannot be obtained.
In order to reduce the reflection of light inputted from a display surface side, it is proposed that an antireflective film is arranged on the aluminum alloy wiring, and Japanese Patent Application Laid-Open No. 2010-79240 discloses an antireflective film formed of an aluminum film and an aluminum nitride film.
In addition, Japanese Patent Application Laid-Open No. 2007-123672 discloses a conductor structure in which an aluminum alloy film containing nickel and nitrogen is formed as an upper layer film.
Meanwhile, in the case where the antireflective film is formed on the wiring in order to reduce the reflection of the light inputted from the outside as described above, when an identification (ID) mark to identify a panel or an array substrate in steps of forming the wiring is to be formed at the same time, the problem is that a focusing operation could not be performed in an exposure apparatus for forming the ID, and various kinds of ID patterns could not be stably formed because reflectivity is low and intensity of the reflected light is low.
Furthermore, Japanese Patent Application Laid-Open No. 2004-317728 discloses a configuration in which an interlayer insulating film of an upper layer of an alignment mark is removed in order to optically detect the alignment mark formed on a wiring layer having a low-reflectivity titanium layer as its uppermost layer.
As described above, when the antireflective film is provided on the wiring layer in order to obtain preferable display characteristics in the environment having the large amount of light inputted from the outside of the display device, the problem is that the ID pattern cannot be stably formed on the wiring layer.